The present invention relates to a ball bat, and more particularly to a ball bat, which is made of a fiber-reinforced plastic and is designed to provide a better elasticity and to prevent the shock wave of striking a ball from transmitting to the player's hands holding the bat.
A wooden bat is susceptible to breakage upon hitting a ball even though it provides a better elastic power. On the other hand, a metal bat with a hollow interior provides a better rigidity to make it less susceptible to breakage upon hitting a ball at the expense of elasticity thereof. In addition, a metal bat is defective in that its weight can not be easily and precisely controlled in the course of manufacture thereof. Therefore, a bat made of a fiber-reinforced plastic material has been introduced. The fiber-reinforced plastic bat is characterized in that its weight can be controlled more precisely and that it provides a better strength than a wooden bat. However, the rigidity of the fiber-reinforced plastic bat can not be controlled precisely.
It is a well-known fact a bat bends instantaneously upon hitting a ball, which is subsequently carried by the hitting portion of the bat while the diametric size of the ball is reduced to about three quarters of the size at the threshold of its contact with the bat. The elastic force of the bat is said to reach an ultimate limitation when the bat, which has hit a ball, stops deflecting. Under this condition, the striking force of a player against the ball begins transmitting to the ball so that the ball has power to fly as far as possible. Accordingly, if a bat is provided with excessive rigidity and elastic force, the ball which has been hit by the bat tens to leave the bat before the striking force of the player has a chance to be transmitted to power the ball. As a result, the ball is not able to fly very far. On the other hand, if a bat is not provided with sufficient rigidity and elasticity, it tends to bend excessively upon hitting a ball, thereby resulting in a prolonged contact of the ball with the bat. As a result, the striking force of a player is unable to concentrate on the ball, which can not fly very far accordingly.
The thickness of ball-hitting portion of a prior art bat of a fiber-reinforced plastic material is greatly increased to avert the breakage of the bat upon hitting a ball. As a result, the rigidity of the bat is excessively enhanced to an extent that the striking force of a player fails to exert on the ball.
Furthermore, the outer layers of a prior art bat are generally made of fiber boards pre-impregnated in epoxy resin and are therefore uniform in construction throughout. Therefore, the shock generated at ball-hitting portion of the bat by impact of a ball can be transmitted without obstruction to the handle portion of the bat, resulting in a possible injury to the hands holding the bat.